/*******************************************************************************
 * Copyright (c) 2005, 2010 IBM Corporation and others. All rights reserved. This program and the
 * accompanying materials are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html Contributors: IBM Corporation - initial API and
 * implementation Jens Lukowski/Innoopract - initial renaming/restructuring
 *******************************************************************************/
package org.eclipse.wst.sse.ui.internal.derived;

import org.eclipse.jface.text.DefaultInformationControl;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.TextPresentation;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Drawable;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Display;
import org.eclipse.wst.sse.ui.internal.Logger;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.Iterator;

/*
 * Copied from org.eclipse.jdt.internal.ui.text.HTMLTextPresenter Modifications were made to use own
 * Logger to log exception, and the ellipses constant
 */
public class HTMLTextPresenter implements DefaultInformationControl.IInformationPresenter,
    DefaultInformationControl.IInformationPresenterExtension {
  private static final String ELLIPSES = "..."; //$NON-NLS-1$
  private static final String LINE_DELIM = System.getProperty("line.separator", "\n"); //$NON-NLS-1$ //$NON-NLS-2$

  private int fCounter;
  private boolean fEnforceUpperLineLimit;

  public HTMLTextPresenter(boolean enforceUpperLineLimit) {
    super();
    fEnforceUpperLineLimit = enforceUpperLineLimit;
  }

  public HTMLTextPresenter() {
    this(true);
  }

  protected Reader createReader(String hoverInfo, TextPresentation presentation) {
    return new HTML2TextReader(new StringReader(hoverInfo), presentation);
  }

  protected void adaptTextPresentation(TextPresentation presentation, int offset, int insertLength) {

    int yoursStart = offset;
    int yoursEnd = offset + insertLength - 1;
    yoursEnd = Math.max(yoursStart, yoursEnd);

    Iterator e = presentation.getAllStyleRangeIterator();
    while (e.hasNext()) {

      StyleRange range = (StyleRange) e.next();

      int myStart = range.start;
      int myEnd = range.start + range.length - 1;
      myEnd = Math.max(myStart, myEnd);

      if (myEnd < yoursStart)
        continue;

      if (myStart < yoursStart)
        range.length += insertLength;
      else
        range.start += insertLength;
    }
  }

  private void append(StringBuffer buffer, String string, TextPresentation presentation) {

    int length = string.length();
    buffer.append(string);

    if (presentation != null)
      adaptTextPresentation(presentation, fCounter, length);

    fCounter += length;
  }

  private String getIndent(String line) {
    int length = line.length();

    int i = 0;
    while (i < length && Character.isWhitespace(line.charAt(i)))
      ++i;

    return (i == length ? line : line.substring(0, i)) + " "; //$NON-NLS-1$
  }

  /**
   * @see IHoverInformationPresenter#updatePresentation(Display display, String, TextPresentation,
   *      int, int)
   * @deprecated Use {@link #updatePresentation(Drawable, String, TextPresentation, int, int)}
   *             instead
   */
  public String updatePresentation(Display display, String hoverInfo,
      TextPresentation presentation, int maxWidth, int maxHeight) {
    return updatePresentation((Drawable) display, hoverInfo, presentation, maxWidth, maxHeight);
  }

  /*
   * @see IHoverInformationPresenterExtension#updatePresentation(Drawable drawable, String,
   * TextPresentation, int, int)
   * 
   * @since 3.2
   */
  public String updatePresentation(Drawable drawable, String hoverInfo,
      TextPresentation presentation, int maxWidth, int maxHeight) {

    if (hoverInfo == null)
      return null;

    GC gc = new GC(drawable);
    try {

      StringBuffer buffer = new StringBuffer();
      int maxNumberOfLines = Math.round(maxHeight / gc.getFontMetrics().getHeight());

      fCounter = 0;
      LineBreakingReader reader = new LineBreakingReader(createReader(hoverInfo, presentation), gc,
          maxWidth);

      boolean lastLineFormatted = false;
      String lastLineIndent = null;

      String line = reader.readLine();
      boolean lineFormatted = reader.isFormattedLine();
      boolean firstLineProcessed = false;

      while (line != null) {

        if (fEnforceUpperLineLimit && maxNumberOfLines <= 0)
          break;

        if (firstLineProcessed) {
          if (!lastLineFormatted)
            append(buffer, LINE_DELIM, null);
          else {
            append(buffer, LINE_DELIM, presentation);
            if (lastLineIndent != null)
              append(buffer, lastLineIndent, presentation);
          }
        }

        append(buffer, line, null);
        firstLineProcessed = true;

        lastLineFormatted = lineFormatted;
        if (!lineFormatted)
          lastLineIndent = null;
        else if (lastLineIndent == null)
          lastLineIndent = getIndent(line);

        line = reader.readLine();
        lineFormatted = reader.isFormattedLine();

        maxNumberOfLines--;
      }

      if (line != null && buffer.length() > 0) {
        append(buffer, LINE_DELIM, lineFormatted ? presentation : null);
        append(buffer, ELLIPSES, presentation);
      }

      return trim(buffer, presentation);

    } catch (IOException e) {
      Logger.log(Logger.WARNING_DEBUG, e.getMessage(), e);
      return null;

    } finally {
      gc.dispose();
    }
  }

  private String trim(StringBuffer buffer, TextPresentation presentation) {

    int length = buffer.length();

    int end = length - 1;
    while (end >= 0 && Character.isWhitespace(buffer.charAt(end)))
      --end;

    if (end == -1)
      return ""; //$NON-NLS-1$

    if (end < length - 1)
      buffer.delete(end + 1, length);
    else
      end = length;

    int start = 0;
    while (start < end && Character.isWhitespace(buffer.charAt(start)))
      ++start;

    buffer.delete(0, start);
    presentation.setResultWindow(new Region(start, buffer.length()));
    return buffer.toString();
  }
}
